(a) Field
Aspects of embodiments of the present invention relate to a scan driver and a display device including the scan driver.
(b) Description of the Related Art
Among flat panel displays, the organic light emitting diode (OLED) display, which displays images by using OLEDs that generate light by recombining electrons and holes, has a fast response speed, low power consumption, and excellent emission efficiency, luminance, and viewing angle, such that usage thereof has recently been expanded. Generally, the OLED display is classified as a passive matrix OLED (PMOLED) or an active matrix OLED (AMOLED) according to a driving method of the OLEDs.
The PMOLED uses a method in which an anode and a cathode are formed to cross each other and cathode lines and anode lines are selectively driven. In contrast, the AMOLED uses a method in which a thin film transistor and a capacitor are integrated in each pixel and a voltage is maintained by a capacitor. The PMOLED has a simple structure and a low cost. However, it is difficult to realize a PMOLED panel of a large size or high accuracy. In contrast, with the AMOLED it is possible to realize a panel of a large size or high accuracy. However, it is difficult to technically realize the control method of the AMOLED display, which results in a comparatively higher cost than the PMOLED display.
In terms of resolution, contrast, and operation speed, the current trend is toward the AMOLED display where respective unit pixels selectively turn on or off. The AMOLED display may include a display panel including a plurality of pixels arranged in a matrix format and driving circuits transmitting image data signals and scan signals to the pixels to display an image. In addition, the driving circuits may include a data driver transmitting the image data signals through data lines connected to the pixels and a scan driver transmitting scan signals through scan lines connected to the pixels for activating each of the pixels to display the image according to a respective one of the image data signals.
In general, the scan driver has a complicated circuit structure to sequentially transmit correct scan signals to the pixels included in the display panel for each pixel line such that an area occupied by the scan driver is large in comparison to the other driving circuits. In addition, when manufacturing a high resolution display device integrating a large number of pixels for the same panel size, space that cannot be used by other circuits (such as dead space) is increased by a circuit area that is occupied by the scan driver such that it is difficult to manufacture the display device to be ultra-light and as a thin film display device.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the present invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.